This project will examine the development of cognitive and neural processes underlying reward-based decision-making. Incentive-based rewards can bias decisions (Montague et al.,1996) with top-down goal directed processes (cognitive control;Miller &Cohen, 2001) or by bottom-up processes related to the predictability of information (reinforcement learning;Montague et al., 1996;Reynolds et al., 2001). We will use the differential development of these systems over childhood to further dissociate the cognitive and neural processes underlying reward-based decisions. We will use a simple two-choice decision task and manipulate reward magnitude, reward uncertainty and reward rate in making a particular response choice. Formal models of reinforcement learning and principles of decision making (diffusion model) together with functional neuroimaging will be used to precisely characterize cognitive and neural processes underlying decision making and constrain a prior hypotheses and interpretations of results. We hypothesize that decisions in childhood are largely driven by bottom-up (reinforcement mechanisms) rather than top-down goal directed behavior due to an inefficient, less mature cognitive control system in children. As such decisions will be optimized by immediate reward (exploitive), but uncertainty or delay in reward will lead to suboptimal performance. Specific Aim 1) To examine the development of cognitive and neural processes underlying decisions as a function of reward magnitude. Specific Aim 2) To examine the development of cognitive and neural processes underlying decisions as a function of reward frequency and uncertainty. Specific Aim 3) To examine the development of cognitive and neural processes underlying decisions as a function of reward rate.